in .xinitrc got things going for the desktop here. As mentioned in an earlier post this only worked with the startx command because these
settings only kick in after loging in with a user. Too late for DMs like KDM/GDM etc..

Somewhere I found a hint (guess it was Archlinux Wiki) to set the xrandr options into /usr/share/config/kdm/Xsetup for KDM. Now I can boot up without KDM turning into a black screen.

Looks like xrandr --listproviders is not showing up anything when i run startx with the new xorg.conf.
I get: Could not find provider with name Intel.
I tried also modesettings and i get same error but with modesetting instead of Intel.
If i try to run xrandr --listproviders while black screen it couldn't connect to display :0.0.

1. Make sure you have CONFIG_DRM=YES in your kernel
2. Make sure that your BusID in Section "Device" for both "nvidia" and "intel" are correct
3. Uncomment AllowEmptyInitialConfiguration in xorg.conf
4. Print how the output of xrandr --listproviders look like after startx.

Where's the point? KDE starting correctly, I can clone display to the external HDMI monitor BUT i can not set anymore a large desktop on two screens :/ My external Monitor on HDMI has a black screen, and turn off.

Well, I just bought a laptop with optimus technology, and I tried bumblebee and didn`t like it. I read around and I understand that it is now possible to use the nvidia gpu without bumblebee even though my laptop lacks a hardware muxer to disable the intel.
So and followed all the instructions here but couldn' t get it to work. I uninstalled xdm and bumblebee to make things simplier.

CONFIG_DRM=y
CONFIG_DRM_KMS_HELPER=m
CONFIG_DRM_KMS_FB_HELPER=y
# CONFIG_DRM_LOAD_EDID_FIRMWARE is not set
# CONFIG_DRM_I2C_CH7006 is not set
# CONFIG_DRM_I2C_SIL164 is not set
# CONFIG_DRM_I2C_NXP_TDA998X is not set
# CONFIG_DRM_TDFX is not set
# CONFIG_DRM_R128 is not set
# CONFIG_DRM_RADEON is not set
# CONFIG_DRM_NOUVEAU is not set
CONFIG_DRM_I810=m
CONFIG_DRM_I915=m
CONFIG_DRM_I915_KMS=y
CONFIG_DRM_I915_FBDEV=y
# CONFIG_DRM_I915_PRELIMINARY_HW_SUPPORT is not set
# CONFIG_DRM_I915_UMS is not set
# CONFIG_DRM_MGA is not set
# CONFIG_DRM_SIS is not set
# CONFIG_DRM_VIA is not set
# CONFIG_DRM_SAVAGE is not set
# CONFIG_DRM_VMWGFX is not set
# CONFIG_DRM_GMA500 is not set
# CONFIG_DRM_UDL is not set
# CONFIG_DRM_AST is not set
# CONFIG_DRM_MGAG200 is not set
# CONFIG_DRM_CIRRUS_QEMU is not set
# CONFIG_DRM_QXL is not set
# CONFIG_DRM_BOCHS is not set

I also have x11-drivers/xf86-video-intel, xf86-video-modesetting, nvidia-drivers and x11-base/xorg-drivers (with VIDEO_CARDS="intel modesetting nvidia") on their latest versions:

Section "Screen"
Identifier "nvidia"
Device "nvidia"
# Uncomment this line if your computer has no display devices connected to
# the NVIDIA GPU. Leave it commented if you have display devices
# connected to the NVIDIA GPU that you would like to use.
Option "UseDisplayDevice" "none"
EndSection

I'm glad I'm not the only one who's spent more than one weekend trying to get proprietary nvidia-drivers working. I don't have access to the machine I'm using right now, but when I get home tonight I'm excited to try what I've seen in this thread. I'll post my results either way; if I get it working I'm going to update the article on the wiki so that others can have an easier time...who wants to spend more time than they need to trying to set up multiple monitors to be productive?

logistiker, Thanks for the reply. I had pretty much given up on the issue. It looks like I'll have to try to get it working using advice from that thread. It also looks like I had my configuration right. I think the thing I did wrong was not referencing the EDID correctly (or possibly generating an EDID that was incorrect).

If you have the time, I'm sure myself and the Gentoo community would appreciate you writing up an EDID guide so that people here in the forums can point others to it as a reference. Or if you want to write out the necessary steps on here for me, I'll put it in the wiki (if you give me your permission). _________________Some stuff I've added to wiki.gentoo.org: http://bit.ly/1nPrkyc
My website: http://www.digitalsurvival.us
Stage7 (automatic Gentoo Installer) Project Page: https://github.com/DigitalSurvival/Stage7

logistiker, Thanks for the reply. I had pretty much given up on the issue. It looks like I'll have to try to get it working using advice from that thread. It also looks like I had my configuration right. I think the thing I did wrong was not referencing the EDID correctly (or possibly generating an EDID that was incorrect).

If you have the time, I'm sure myself and the Gentoo community would appreciate you writing up an EDID guide so that people here in the forums can point others to it as a reference. Or if you want to write out the necessary steps on here for me, I'll put it in the wiki (if you give me your permission).